09 February 2016

I recently had occasion to prepare a talk on the various causes of Altered Mental Status. As it happens, EM:RAP had a nice Continuous Core Content segment recently on the same topic. (Don't listen to EM:RAP? You should. Want to try it for free? Rob Orman of ERCast has an offer for a three month free trial. Use the code ERTHANKS.)* They used a practical case-based format to structure the approach, which I like, but also fell back on the old mnemonic of AEIOU TIPS. God I hate that mnemonic. It's so haphazard and utterly disorganized: just like the typical approach to AMS.

A — Alcohol/Acidosis (not the same thing or in any way logically connected)

E — Endocrine/Epilepsy/Electrolytes/Encephalopathy (E is a common letter?)

This is just terrible. Too many things thrown into too few headers with absolutely no logical connection between any of them and criminally incomplete to boot. Bad for learners, and pretty useless for recall too. My approach was to ask myself, well, AMS basically means the brain's not working right, right? Let's group the causes of AMS by the mechanism by which they make the brain not work right. So that's what I did. It is offered here for your perusal and amusement and maybe even use.

Things your brain needs to live and function

↓ Oxygen/Glucose (fix these immediately)

Things that squish the brain

Blood where it should not be: Subdural, Epidural, Intracerebral, Subarachnoid

Blood that has clotted where it should not: Dural Sinus Thrombosis

Masses and tumors

Obstructive Hydrocephalus

Edema: Traumatic, posthypoxic, hypertensive, vasogenic, PRES

Bad things living in the brain

Meningitis

Encephalitis: viral, inflammatory, autoimmune

Abscesses

Syphilis/Amebas/Cysts

Primary brain not workings

Acute Ischemic Stroke

Concussion/Diffuse Axonal Injury

Seizure, Status epilepticus (may not be convulsive), post-ictal state

Migraine

Degenerative conditions: MS, Parkinson’s, TBI, Dementias sundry

BONUS POINTS for this plus another cause

Delirium and Encephalopathies and Various Failures of Homeostasis

Sepsis and other shock states (hypoperfusion)

Systemic infection without sepsis

Fever, Hyperthermia and Hypothermia

Dehydration, ↑Na, ↑Glucose (HONK and/or DKA)

↑/↓ Ca, ↓Na, ↑/↓K

↑/↓ Thyroid, Adrenal Crisis

Bad Things in the Blood

EtOH (rare)

Endogenous bad things

↑CO2, Uremia, Ammonia

Medicines that can mess you up when used as intended

Opiates, benzodiazepines, imidazopyridines (ambien et al)

Medicines that will mess you up when you get too much of them

Lithium, Tricyclics, Anticonvulsants, Antihistamines, Salicylates

Things that you are not allowed to have in your blood because it is a crime

Maybe You’re Just Crazy?

Conversion Disorder

Psychosis/Mania

Malingering

These are last on the list for a reason

This is by no means an exhaustive list (I get exhausted just thinking about all the bad things in the blood) but rather a mode of thinking about the potential causes for a patient with AMS. Also, the astute reader will note that it is neither sorted by frequency nor by approach to workup (though that would be fun to categorize. "Things you will see on CT"; "Things you will diagnose when the hospitalist forces you to do an LP"; "Things that will require a Neuro consult" etc.) Enjoy, and remember, no matter what, always check the fecking glucose.

*I'm not getting paid by EM:RAP. But I will probably make Rob buy the first round the next time we are both at the same conference.

Shadowfax

About me: I am an ER physician and administrator living in the Pacific Northwest. I live with my wife and four kids. Various other interests include Shorin-ryu karate, general aviation, Irish music, Apple computers, and progressive politics. My kids do their best to ensure that I have little time to pursue these hobbies.

Disclaimer

This blog is for general discussion, education, entertainment and amusement. Nothing written here constitutes medical advice nor are any hypothetical cases discussed intended to be construed as medical advice. Please do not contact me with specific medical questions or concerns. All clinical cases on this blog are presented for educational or general interest purposes and every attempt has been made to ensure that patient confidentiality and HIPAA are respected. All cases are fictionalized, either in part or in whole, depending on how much I needed to embellish to make it a good story to protect patient privacy.

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